76 ideas
| 19396 | Wisdom is knowing all of the sciences, and their application [Leibniz] |
| 14888 | Wisdom prevents us from being ruled by the moment [Nietzsche] |
| 14863 | Unlike science, true wisdom involves good taste [Nietzsche] |
| 14890 | Suffering is the meaning of existence [Nietzsche] |
| 14861 | Philosophy ennobles the world, by producing an artistic conception of our knowledge [Nietzsche] |
| 14887 | You should only develop a philosophy if you are willing to live by it [Nietzsche] |
| 14885 | The first aim of a philosopher is a life, not some works [Nietzsche] |
| 14889 | Philosophy is pointless if it does not advocate, and live, a new way of life [Nietzsche] |
| 14862 | Philosophy is more valuable than much of science, because of its beauty [Nietzsche] |
| 14878 | It would better if there was no thought [Nietzsche] |
| 14881 | Why do people want philosophers? [Nietzsche] |
| 14876 | Philosophy is always secondary, because it cannot support a popular culture [Nietzsche] |
| 14860 | Kant has undermined our belief in metaphysics [Nietzsche] |
| 14859 | If philosophy controls science, then it has to determine its scope, and its value [Nietzsche] |
| 10073 | There cannot be a set theory which is complete [Smith,P] |
| 14880 | Logic is just slavery to language [Nietzsche] |
| 10616 | Second-order arithmetic can prove new sentences of first-order [Smith,P] |
| 10074 | A 'total function' maps every element to one element in another set [Smith,P] |
| 10612 | An argument is a 'fixed point' for a function if it is mapped back to itself [Smith,P] |
| 10605 | Two functions are the same if they have the same extension [Smith,P] |
| 10075 | A 'partial function' maps only some elements to another set [Smith,P] |
| 10076 | The 'range' of a function is the set of elements in the output set created by the function [Smith,P] |
| 10615 | The Comprehension Schema says there is a property only had by things satisfying a condition [Smith,P] |
| 10595 | A 'theorem' of a theory is a sentence derived from the axioms using the proof system [Smith,P] |
| 10602 | A 'natural deduction system' has no axioms but many rules [Smith,P] |
| 10613 | No nice theory can define truth for its own language [Smith,P] |
| 10079 | A 'bijective' function has one-to-one correspondence in both directions [Smith,P] |
| 10077 | A 'surjective' ('onto') function creates every element of the output set [Smith,P] |
| 10078 | An 'injective' ('one-to-one') function creates a distinct output element from each original [Smith,P] |
| 10070 | If everything that a theory proves is true, then it is 'sound' [Smith,P] |
| 10086 | Soundness is true axioms and a truth-preserving proof system [Smith,P] |
| 10596 | A theory is 'sound' iff every theorem is true (usually from true axioms and truth-preservation) [Smith,P] |
| 10598 | A theory is 'negation complete' if it proves all sentences or their negation [Smith,P] |
| 10597 | 'Complete' applies both to whole logics, and to theories within them [Smith,P] |
| 10069 | A theory is 'negation complete' if one of its sentences or its negation can always be proved [Smith,P] |
| 10609 | Two routes to Incompleteness: semantics of sound/expressible, or syntax of consistency/proof [Smith,P] |
| 10087 | A theory is 'decidable' if all of its sentences could be mechanically proved [Smith,P] |
| 10088 | Any consistent, axiomatized, negation-complete formal theory is decidable [Smith,P] |
| 10080 | 'Effective' means simple, unintuitive, independent, controlled, dumb, and terminating [Smith,P] |
| 10081 | A set is 'enumerable' is all of its elements can result from a natural number function [Smith,P] |
| 10083 | A set is 'effectively enumerable' if a computer could eventually list every member [Smith,P] |
| 10084 | A finite set of finitely specifiable objects is always effectively enumerable (e.g. primes) [Smith,P] |
| 10085 | The set of ordered pairs of natural numbers <i,j> is effectively enumerable [Smith,P] |
| 10601 | The thorems of a nice arithmetic can be enumerated, but not the truths (so they're diffferent) [Smith,P] |
| 10600 | Being 'expressible' depends on language; being 'capture/represented' depends on axioms and proof system [Smith,P] |
| 10599 | For primes we write (x not= 1 ∧ ∀u∀v(u x v = x → (u = 1 ∨ v = 1))) [Smith,P] |
| 10610 | The reals contain the naturals, but the theory of reals doesn't contain the theory of naturals [Smith,P] |
| 10619 | The truths of arithmetic are just true equations and their universally quantified versions [Smith,P] |
| 10618 | All numbers are related to zero by the ancestral of the successor relation [Smith,P] |
| 10608 | The number of Fs is the 'successor' of the Gs if there is a single F that isn't G [Smith,P] |
| 10849 | Baby arithmetic covers addition and multiplication, but no general facts about numbers [Smith,P] |
| 10850 | Baby Arithmetic is complete, but not very expressive [Smith,P] |
| 10851 | Robinson Arithmetic 'Q' has basic axioms, quantifiers and first-order logic [Smith,P] |
| 10852 | Robinson Arithmetic (Q) is not negation complete [Smith,P] |
| 10068 | Natural numbers have zero, unique successors, unending, no circling back, and no strays [Smith,P] |
| 10603 | The logic of arithmetic must quantify over properties of numbers to handle induction [Smith,P] |
| 10604 | Incompleteness results in arithmetic from combining addition and successor with multiplication [Smith,P] |
| 10848 | Multiplication only generates incompleteness if combined with addition and successor [Smith,P] |
| 14869 | If some sort of experience is at the root of matter, then human knowledge is close to its essence [Nietzsche] |
| 10617 | The 'ancestral' of a relation is a new relation which creates a long chain of the original relation [Smith,P] |
| 19397 | Perfect knowledge implies complete explanations and perfect prediction [Leibniz] |
| 14875 | Belief matters more than knowledge, and only begins when knowledge ceases [Nietzsche] |
| 14866 | It always remains possible that the world just is the way it appears [Nietzsche] |
| 14872 | Our knowledge is illogical, because it rests on false identities between things [Nietzsche] |
| 14879 | The most extreme scepticism is when you even give up logic [Nietzsche] |
| 14873 | If we find a hypothesis that explains many things, we conclude that it explains everything [Nietzsche] |
| 14868 | Our primary faculty is perception of structure, as when looking in a mirror [Nietzsche] |
| 14870 | We experience causation between willing and acting, and thereby explain conjunctions of changes [Nietzsche] |
| 14867 | It is just madness to think that the mind is supernatural (or even divine!) [Nietzsche] |
| 14884 | The shortest path to happiness is forgetfulness, the path of animals (but of little value) [Nietzsche] |
| 14886 | Education is contrary to human nature [Nietzsche] |
| 14883 | We should evaluate the past morally [Nietzsche] |
| 14882 | Protest against vivisection - living things should not become objects of scientific investigation [Nietzsche] |
| 14865 | We do not know the nature of one single causality [Nietzsche] |
| 14871 | Laws of nature are merely complex networks of relations [Nietzsche] |
| 14864 | The Greeks lack a normative theology: each person has their own poetic view of things [Nietzsche] |